The present invention relates to aspects of an invention associated with a two-pack urethane foam composition for reinforcing a closed sectional structure of the body of a vehicle, e.g., automobile, by filling a urethane foam, by injecting the two-pack urethane foam composition, into the closed sectional structure thereof.
More particularly, one aspect of the invention relates to a two-pack urethane foam composition which is composed of a two-pack of a polyol compound as a major component and a polyisocyanate compound as a curing agent, and which can form a urethane foam by foaming and curing upon injecting (applying) immediately after mixing the two components at ambient temperature. On the other hand, other aspects of the invention relate to an injection method for injecting the two-pack urethane foam composition, a cured urethane foam-filled vehicle body member having an opening for confirming the injecting and filling of the two-pack urethane foam composition, a cured urethane foam-filling confirming method for confirming the appropriateness of a filling volume of the two-pack urethane foam composition, and a two-pack urethane foam composition injecting apparatus and method capable of automatically injecting and filling the two-pack urethane foam composition into the closed sectional structure of the vehicle body.
In recent years, the automobile industry has been required to ensure the rigidity of an entire vehicle body for increasing the safety of automobiles and improving a soundproof property of a riding space. In order to achieve these requirements, demands have be made to provide the intensity and the rigidity and the soundproof property to a portion where a variety of loads such as impact and so on are imposed, such as a center pillar having a closed sectional structure, a front pillar of a vehicle body having a closed sectional structure and so on. Moreover, in order to protect riders from impact, a crushable zone has to be provided on each of the front and rear sides of the vehicle body and a solid safety cell has to be configured for a cabin where the riders are seated in order to ensure a riding space for the riders.
On the other hand, problems may arise in that the weight of the vehicle body is increased and the fuel economy becomes poorer if a thick panel is used as each of the pillar, chassis or the like having a closed sectional structure in order to improve the rigidity and the soundproof property of the cabin.
Therefore, it has been suggested to develop structures and methods for increasing the rigidity of the vehicle body while keeping the thick panel of the pillar of the vehicle body and so on thin, for instance, by injecting and filling a cured urethane foam into the closed sectional structure of the pillar thereof and so on by using the above two-pack urethane foam composition. In combination of development of making the vehicle body lightweight, it has also been considered to inject and fill a urethane foam into a closed sectional structure of a roof portion or a locker portion or the like, in addition to the pillar and so on.
Various problems, however, may result in injecting the two-pack urethane foam composition into the closed sectional structure.
For instance, when the two-pack urethane foam composition is injected in a fluid state, there are occasions that the injected composition leaks outside or expands from the injection port due to a back flow. The injected composition leaks or expands even from a small gap of the closed sectional structure so that there is the risk that the appearance of the automobile may be impaired (hereinafter referred to as the first problem).
It has now been found by the present inventors that the two-pack urethane foam composition does not leak or expand from small gaps in an injecting portion, if any, due to becoming cured to an appropriate level of viscosity immediately after injection by limiting foaming characteristics of the two-pack urethane foam composition, particularly a cream time and a rise time, as well as adjusting the specific gravity of the filed urethane foam to become 0.6 to 0.01 by adjusting the amount of the foaming agent.
When such a two-pack urethane foam composition of a curable type having a high reactivity at ambient temperature (0xc2x0 C.-50xc2x0 C.) is used, it has been found to raise a practically significant problem that, when it is discharged or injected from a conventional two-pack mixing apparatus, there are occasions in which the two-pack urethane foam composition cures in the mixing apparatus during injecting on site, and thus clogs the mixing apparatus during the injecting process (hereinafter referred to as the second problem).
It is designed as a matter of course to inject a predetermined amount of the two-pack urethane foam composition, corresponding to the volume of the closed sectional structure to be injected and filled with the composition, with a foaming rate and other foaming conditions of the two-pack urethane foam composition taken into account. If an unpredictable problem would occur with an injecting apparatus or the like; however, there may result an unpredictable occasion that the filling volume of the cured urethane foam becomes less than the desired range and a hollow portion may result, thereby making it difficult to reach the designed rigidity. It is considered that the lack of the filling volume may also arise due to accidental damage of a partition plate disposed in the closed sectional structure.
In actual cases, however, the present situation resides in that there is no manner of preventing the lack of such filling volume of the urethane foam in advance, and that the appropriateness or inappropriateness of the filling volume can be judged for the first time by carrying out impact tests or by measuring the rigidity of an actual car or analyzing the vibration thereof after the production line. Therefore, the problem is that the design intensity and rigidity of the automobile cannot be ensured during the production line (hereinafter referred to as the third problem).
Furthermore, in general, the production of automobiles is carried out by mass production by the transfer and assembly method using a belt conveyor on the basis of the division of work. In order to adapt a production line to such a mass production, however, it is required to develop an injecting apparatus and an injecting method for injecting and filling a two-pack urethane foam composition into the closed sectional structure of the vehicle body (hereinafter referred to as the fourth problem).
The present invention has been completed with the foregoing facts taken into account and has the major object to solve the various problems that may arise upon injecting and filling a two-pack urethane foam composition into a structural member to be injected and filled, such as a closed sectional structure of a vehicle body, etc.
More specifically, the present invention in one aspect has objects to provide a two-pack urethane foam composition and an injection method for injecting the two-pack urethane foam composition, which can prevent the injected composition from being leaked outside or expanding from the inside due to a back flow of the injected composition, upon injecting the two-pack urethane foam composition into the structural member to be injected and filled.
In another aspect, the present invention has an object to provide an injection process for injecting the two-pack urethane foam composition in the structural member to be injected and filled, which can inject it into the structural member in a smooth way completely without causing clogging as well as which does not cause the injected composition from being leaked outside and expanding due to a back flow thereof upon injection of the composition into the structural member.
Moreover, in a further aspect, the present invention has other objects to provide a cured urethane foam-filled vehicle body member, an injecting method for injecting and filling the cured urethane foam into the vehicle body member, and a cured urethane foam-filled confirming method for confirming the filling of a cured urethane foam therein, which can confirm the appropriateness of the filling volume so as to adapt to the volume of the inside of the closed sectional structure of the vehicle body, upon injecting the two-pack urethane foam composition into the inside of the closed sectional portion thereof having a closed sectional structure and injecting and filling the closed sectional structure with the cured urethane foam by foaming and curing the two-pack urethane foam composition.
Furthermore, the present invention has still further objects to provide a injecting apparatus and a injecting method for injecting and filling the two-pack urethane foam composition in the closed sectional structure of the vehicle body, which are adapted to a mass production of vehicles including, e.g., automobiles.
(Injection Method for Injecting Two-Pack Urethane Foam Composition)
In order to solve the first problem as described above, the present inventors have made extensive review and studies with the attempt to solve the problems associated with the leakage of the two-pack urethane foam composition outside and expanding due to a back flow thereof upon injecting the two-pack urethane foam composition into an injection port of a structural member to be injected and filled, which is not limited to and includes a closed sectional structure of a pillar portion of the vehicle body member. As a result of such extensive review and studies, it has been found that the above objects can be achieved by providing a unique injection port for injecting the two-pack urethane foam composition, or providing a portion in the vicinity of the injection port. Therefore, this invention has been completed on the basis of this finding.
More specifically, in order to prevent the once injected composition from leaking and expanding outside from the injection port of the structural member that has been injected and filled during the injecting method with the two-pack urethane foam composition, which foams and cures therein, the present invention provides the injection method for injecting the two-pack urethane foam composition, characterized in that: (i) a shut-off plate for the injection port is mounted on the inner side of the structural member to be injected and filled so as to open or close the injection port; (ii) a rubber-formed member having a cross cut portion is inserted into the injection port so as to open or close the injection port; or (iii) a check valve that allows a fluid to pass only in one direction is mounted on the injection port.
With the requirements for the reinforcement of the rigidity inside the such pillars and improvements in soundproofproperties taken into account, the present inventors have made extensive review and studies on the two-pack urethane foam compositions having excellent properties in foaming and curing, by focusing on the first problem resulting from the properties of the two-pack urethane foam composition itself. This can solve the first problem and meet the requirements of the automobile industry, as well as provide a high level of efficiency in injection of a closed sectional structure and a high degree of rigidity and excellent soundproofproperties. As a result, the following findings have been made.
It has first been found that, even if there would be used a foaming agent of a curable type under ambient temperature conditions, which can generally generate gases under thermal conditions, in place of a foaming agent of a type that has usually been used conventionally under ambient temperature conditions (such as water or of a hydrogen-containing halogenated hydrocarbon type or of a low-boiling temperature hydrocarbon type, etc.), the urethane foam can be formed upon mixing the two-pack urethane foam composition at ambient temperature by allowing the foaming agent to work at a sufficiently high level by the reaction heat produced upon an instantaneous reaction between the polyol compound as the major component (a) with the polyisocyanate compound as the curing agent (b), and by defining the specific gravity of the cured urethane foam by adjusting the amount of the foaming agent.
In this case, too, it has been found, however, that the problem with the leakage of the injected composition still remains unsolved. Therefore, as a result of further review and studies, the present inventors have found that the addition of an amine compound of a particular weight ratio having an active hydrogen atom (xe2x80x94NH2xe2x80x94 or xe2x80x94NHxe2x80x94) on the main component side at a particular rate can produce an appropriate soft or hard urethane foam that can prevent the once injected composition from leaking outside and expanding through a gap due to its excessive level of viscosity and an appropriate speed of foaming and curing and that can be adapted to the purposes to achieve reinforcement performance and soundproof properties.
More specifically, the present invention has been completed on the basis of the above findings and provides a two-pack urethane foam composition for urethane foam, comprising (a) a polyol compound as a major component and (b) a polyisocyanate compound as the curing agent, which can produce a urethane foam by reaction of the two components in the presence of the foaming agent. The foaming agent to be used for this purpose may include a chemical foaming agent and inorganical forming agent of a thermally decomposable type, which may be used singly or as a mixture in combination of two or more kinds thereof. The amount of the foaming agent is to be adjusted so that the resulting cured urethane foam is to have a specific gravity in the range of from 0.6 to 0.01. Further, the two-pack urethane foam composition may comprise (a) the above major component and (b) the above curing agent, wherein an amine compound having-a number-average molecular weight of 110 or more and at least one of an amino (xe2x80x94NH2xe2x80x94) group and an imino (xe2x80x94NHxe2x80x94) group is formulated with the major component (a). The amine compound is selected so that its amino (xe2x80x94NH2xe2x80x94) group and/or the imino (xe2x80x94NHxe2x80x94) group is present in an amount of from 0.05% to 3% by weight with respect to the total weight of the above major component (a) and the above curing agent (b), and the amount of the foaming agent is to be adjusted so that the resulting cured urethane foam is to have a specific gravity in the range of 0.6 to 0.01.
As the polyol compound to be used as the major component (a) for the present invention, there may preferably be used a polyether polyol which may be obtained by the additional reaction between an active hydrogen containing compound such as, for example, a poly-valent alcohol, a bisphenol, an aliphatic amine, an aromatic amine, an aliphatic amine having an aromatic ring, or an alicyclic amine, and an alkylene oxide (e.g., one or more selected from ethylene oxide, propylene oxide, butylene oxide and isobutylene oxide).
Further, it is appropriate that the polyol compound may have an average hydroxy group value in the range of, generally, from 150 to 800, preferably from 200 to 600, from the point of view of reinforcement purposes. If the average hydroxy group value of the polyol compound would be smaller than 150, a sufficiently high level of rigidity cannot be achieved. On the other hand, if the average hydroxy group value of the polyol compound would exceed 800, the resulting urethane foam may become brittle.
As the poly-valent alcohol, there may be mentioned, such as a di-valent alcohol, e.g., ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butane diol, pentane diol, hexane diol, neopentyl glycol, cyclohexylene glycol, etc., a tri-valent alcohol, e.g., trimethylol propane, glycerin, etc., a tetra-valent or higher-valent alcohol, e.g., pentaerythritol, sorbitol, methyl glycoside, diglycerin, sucrose, and so on.
As the bisphenol, there may be mentioned, for example, hydroquinone, 1,4-bis(hydroxyethoxy)benzene, bisphenol A, bisphenol F, bisphenol S, 4,4xe2x80x2-dihydroxybiphenyl, 2,2xe2x80x2-bis(4-hydroxyphenyl)hexafluoro-propane, and so on.
As the aliphatic amine, there may be mentioned, for example, ammonia, monoethanol amine, diethanol amine, triethanol amine, polymethylene diamine (e.g., ethylene diamine, diaminobutane, diaminopropane, hexane diamine, dodecane diamine, etc.), polyethylene polyamine (e.g., diethylene triamine, triethylene tetramine, etc.), polyether diamine, and so on.
As the aromatic amine, there may be mentioned, for example, 2,4- or 2,6-diaminotoluene (TDA), crude TDA, 1,2-, 1,3- or 1,4-phenylene diamine, diethyltolylene diamine, 4,4xe2x80x2-diamino diphenyl methane (MDA), crude MDA, 1,5-naphthylene diamine, 3,3xe2x80x2-dichloro-4,4xe2x80x2-diaminophenyl methane, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-diaminodiphenyl cyclohexane, and so on.
As the aliphatic amine having the aromatic ring, there may be mentioned, for example, 1,2-, 1,3- or 1,4-xylene diamine, and so on.
As the alicyclic amine, there may be mentioned, for example, 4,4xe2x80x2-diamino dicyclohexyl methane, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-diamino dicyclohexyl methane, 3-amino-1-cyclohexyl aminopropane, bis(aminomethyl)cyclohexane, isophorone diamine, norbornane diamine, menthene diamine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxa spiro(-5,5-)undecane, and so on.
In addition to the above polyether polyols, there may be used an oligomer having two or more hydroxy groups, such as polyester polyol (a condensed product resulting from condensation reaction between a polycarboxylic acid and a polyhydroxyl compound); a polycarbonate polyol; a polycaprolactone polyol; a polymer polyol denatured with a polybutadiene polyol, an acryl polyol, an ethylenic unsaturated monomer, etc.; and so on.
As the polycarboxylic acid to be used as a raw material for the polyester polyol, there may be mentioned, for example, adipic acid, sebacic acid, dimeric acid, phthalic anhydride, terephthalic acid, isophthalic acid, phthalic acid, trimellitic acid, pyromelic acid, and so on. As the polyhydroxyl compound, there may be illustrated, for example, the poly-valent alcohol to be used for the above polyester polyol, and the polyester polyol itself.
On the other hand, the polyisocyanate compounds as the curing agent (b) for the present invention may include, for example, an aromatic polyisocyanate; an aliphatic or alicyclic polyisocyanate; an aromatic-aliphatic polyisocyanate; a modified product thereof (such as a polyol adduct modified product, e.g., trimethylol propane, castor oil, sucrose, etc., a carbodiimide modified product, an allophanate modified product, a urea modified product, a biuret modified product, an isocyanurate modified product, an oxazolidone modified product, etc.), a urethane prepolymer having a NCO group at its terminal obtainable by the reaction of a polyol compound with an excessive amount of a polyisocyanate compound, and so on.
As the aromatic polyisocyanates, there may be mentioned, for example, 1,3- or 1,4-phenylene diisocyanate, 2,4- and/or 2,6-tolylene diisocyanate (TDI), crude TDI, diphenylmethane-2,4xe2x80x2- and/or -4,4xe2x80x2-diisocyanate (MDI), crude MDI, polymethylene polyphenyl isocyanate, naphthylene-1,5-diisocyanate, triphenylmethane-4,4xe2x80x2,4xe2x80x3-triisocyanate, and so on.
As the aliphatic or alicyclic polyisocyanates, there may be mentioned, for example, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, 4,4xe2x80x2-dicyclohexylmethane diisocyanate, 1,4-cyclohexylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and so on.
As the aromatic-aliphatic polyisocyanates, there may be mentioned, for example, xylylene diisocyanate, tetramethylxylylene diisocyanate, and so on.
Among the polyisocyanates as described above, preferred examples of the polyisocyanates are MDI, crude MDI, sucrose-modified TDI, and carbodiimide-modified MDI. Most preferred one is crude MDI.
The two-pack urethane foam composition for urethane foam according to the present invention may comprise the above major component (a) (the polyol compound) and the curing agent (b) (the polyisocyanate compound), which is usually obtainable by formulating the above amine compound with the major component (a) by reacting the major component (a) in the presence of the foaming agent (in usual cases, to be added to the major component (a)) in a two-pack system to form a urethane foam
It can be noted herein that, although the major component (a) and the curing agent (b) can be varied in mixing, the major component (a) may be selected in usual cases so that the equivalent ratio of the active hydrogen group (OH group) of the major component (a) to the NCO group of the curing agent (b) is 1:0.8-10, and preferably 1:0.9-5.
As the foaming agent to be used in the case (i) above, there may be used, for example, the chemical foaming agent of a thermally decomposable type such as, e.g., dinitroso pentamethylene tetramine (DPT), azo dicarbodiamide (ADCA), p,pxe2x80x2-oxy bisbenzene sulfonyl hydrazide (OBSH), p-toluene sulfonyl hydrazide (TSH), p-toluene sulfonyl acetone hydrazone, hydrazo dicarbonamide, azo bisisobutyronitrile (AIBN), and so on (these may be used together with an accessory agent of a urea type or of a metallic type); and the inorganic foaming agent of a thermally decomposable type (such as sodium hydrogen carbonate, etc., and these may be used as singly or a mixture in combination of two or more kinds). These foaming agents (hereinafter referred to as a xe2x80x9climited foaming agentxe2x80x9d) may be caused to decompose or expand due to the reaction heat generated by the instantaneous reaction between the major component (a) and the curing agent (b), thereby producing gases even without using a separate heating device.
In addition to the limited foaming agent, there may also be used water which has been hitherto used as a foaming agent, or a foaming agent of a hydrogen-containing halogenated hydrocarbon type or a foaming agent of a low-boiling point hydrocarbon type (hereinafter referred to as a xe2x80x9cconventional foaming agentsxe2x80x9d).
When these foaming agents are used, it is of significance that the amount to be used, regardless of their kinds, may be adjusted so that a specific gravity of a cured urethane foam resulting therefrom is in the range of from 0.6 to 0.01, preferably from 0.5 to 0.03. If the foaming agent would be used in the amount so that the specific gravity of the resulting urethane foam to exceeds 0.6, the composition cannot be injected and filled in every corner of a closed sectional structure, thereby failing to contribute to a reduction of costs and a decrease in the weight of the structural member. If the foaming agent would be used in the amount so that the specific gravity of the resulting urethane foam becomes smaller than 0.01, the cured urethane foam injected and filled in the closed sectional structure is likely to be damaged, thereby failing to achieve the purposes of reinforcement and performance of soundproof properties. It is preferred to adjust the amount of the foaming agent so that the specific gravity of the resulting urethane foam is in the range of 0.5 to 0.01 for achieving the purposes of reinforcement, on the one hand, and is in the range of 0.4 to 0.03 for performing the purposes of soundproof properties, on the other hand.
As the amine compounds to be used in the case (ii) above, there may be used the amine compound having at least one of the amino group (xe2x80x94NH2) and the imino group (xe2x80x94NHxe2x80x94), having an average molecular weight of 110 or more, preferably from 120 to 5,000, more preferably from 120 to 1,000, especially from 120 to 500. The amine compounds may be selected from a polyamide and a modified product resulting therefrom, which may be obtained by the condensation reaction between the aliphatic amine, aromatic amine or alicyclic amine or an amine thereof, as illustrated as a raw material for the polyether polyol, and the polycarboxylic acid illustrated as a raw material for the polyether polyol. An alkylene oxide adduct of these amine compounds may also be used.
It is also of significance that the amount of the amine compound to be added may be adjusted so that the amino group (xe2x80x94NHxe2x80x942) and/or the imino group (xe2x80x94NHxe2x80x94) is present in the amine compound in an amount of from 0.05 to 3% by weight, preferably from 0.1 to 1% by weight, with respect to the total amount of the major component (a) and the curing agent (b). If the amount of the amino and/or imino groups is less than 0.05% by weight, the two-pack urethane foam composition may not achieve the effect of preventing the cured urethane foam from leaking and expanding from a gap of a closed sectional structure due to an increased viscosity. If the amount of the amino and/or imino groups exceeds 3% by weight, the mixing of the two-pack urethane foam composition may become insufficient. It is also noted herein that the use of the amine compound having a number-average molecular weight of less than 110 may not achieve the effect of preventing a leakage of the cured urethane foam from a gap of the closed sectional structure.
For the two-pack urethane foam compositions for the present invention, there may be used a catalyst which may be usually used for a so-called urethane reaction. A such catalyst may include, for example, an amine-type catalyst such as, e.g., triethylene diamine, pentamethylene diethyl tetramine, N-ethylmorpholine, diethylethanol amine, 1,8-diaza bicyclo(5.4.0)undecene-7, etc., or a metallic-type catalyst such as, e.g., stannous octylate, dibutyl tin dilaurate, lead octylate, etc. The amount of the catalyst to be used may appropriately range usually from 0.0001% to 5% with respect to the total amount of the composition.
Moreover, as needed, the two-pack urethane foam composition may contain a conventional additive component such as a foam stabilizer, coloring agent (dye or pigment), plasticizer, filler, fire retardant, antioxidant, and so on in an appropriate amount.
(Cured Urethane Foam-Injected Vehicle Body Member and Injecting Method for Filling Cured Urethane Foam)
The present inventors have extensively studied to prevent an occurrence of the problems due to the lack of the filling volume, to provide a vehicle body member having a closed sectional structure reinforced by appropriately injecting and filling a cured urethane foam, and to provide an injecting method for injecting and filling the cured urethane foam. As a result of extensive studies, it has been found that the desired object can be achieved by locating a cured urethane foam-filling confirming opening of a particular dimension in a particular position, of the vehicle body member, for confirming the appropriateness of the filling volume of the cured urethane foam so as to adapt to the volume of the inside of the closed sectional structure. The present invention has been completed on the basis of this finding.
More specifically, the present invention provides a cured urethane foam-filled vehicle body member with the cured urethane foam injected and filled therein by injecting the two-pack urethane foam composition into the closed structure of the vehicle body member having a closed sectional structure, and foaming and curing the cured urethane foam composition injected and filled therein, which is characterized in that the cured urethane foam-filling confirming opening is of an opening size of 10 mm or smaller and is disposed by at most 50 mm from the location at which the cured urethane foam eventually reaches.
Further, the present invention provides an injecting method for injecting the cured urethane foam by injecting the two-pack urethane foam composition into the closed sectional portion of the vehicle body member having the closed sectional structure, and foaming and curing the two-pack urethane foam composition injected and filled therein, which is characterized in that the appropriateness of the filling volume of the cured urethane foam, in order to adapt to the volume of the inside of the closed sectional structure of the vehicle body member, is confirmed by locating a cured urethane foam-filling confirming opening having a dimension of at most 10 mm at a position that is at most 50 mm from the location that the cured urethane foam eventually reaches.
As the vehicle body member with a closed sectional structure according to the present invention, there may be mentioned a structural member, as shown in FIG. 7, such as composed of a connecting member having a front roof 1b (consisting of a roof rail inner and a roof rail outer), a front side roof rail 2b (consisting of a front side outer panel and a side roof rail inner), and a front pillar 3c (consisting of a front side outer panel and a front pillar inner) connected together at their one ends, in which shut-off plates 4b and 5b are disposed inside the front side roof rail 2b and the front pillar 3c, respectively, and the front side roof rail 2b is provided with an injection port 6b. 
As another example, there may be illustrated a structural member as shown in FIG. 8, which is composed of a connecting member having a center pillar 7a (consisting of a center pillar inner and a center pillar outer) and a side roof rail 8a (consisting of a side roof rail inner and a side roof rail outer) connected together, in which the center pillar 7a is provided with a shut-off plate 9, the side roof rail 8a is provided with shut-off plates 10a and 11b, and the center pillar 7a is further provided with an injection port 12a. 
(Cured Urethane Foam-Filling Confirming Method)
The present inventors have made extensive review and studies on various processes and ways of preventing the problems to be caused due to the lack of achieving the filling volume and reinforcing the vehicle body member by appropriately injecting and filling a cured urethane foam therein. As a result, the present inventors came to focus on the fact that heat can be produced together with foaming due to the reaction upon injecting the two-pack urethane foam composition in the closed sectional portion of the vehicle body member having a closed sectional structure, and that the heat produced can elevate the temperature of a panel located at the site of the vehicle body member where the composition was injected and filled in. More specifically, it has been found that a site where the urethane foam is filled in the vehicle body member, and a site where it is not filled in the vehicle body member can be distinguished from each other on the basis of a temperature difference between these two locations. The temperature difference is determined by measuring the temperature in a non-contact way at locations on the side surface of the vehicle body member in the vicinity of the location that the cured urethane foam reaches. Therefore, it can be confirmed whether the filling volume is appropriate as to adapt to the volume of the interior of the closed sectional structure by distinguishing the filled site from the non-filled site. The present invention in another aspect has now been completed on the basis of this finding.
In other words, the present invention provides a cured urethane foam-filling confirming method for confirming the injecting or filling of a cured urethane foam which is characterized in that, upon injecting and filling the two-pack urethane foam composition in the closed sectional portion of the vehicle body member having a closed sectional structure, and allowing the composition to foam and cure, the temperature is measured in a non-contact way from the outside at locations on the side surface of a vehicle body to determine a time difference between a filled site where the urethane foam is injected and filled in the vehicle body member and a non-filled site where it is not injected and filled in the vehicle body member, in order to confirm the appropriateness of a filling volume, as to whether the filling volume adapts to the volume of the interior of a closed sectional structure of the vehicle body member. The appropriateness or inappropriateness of the filling volume is confirmed on the basis of the temperature difference between the filled site and the non-filled site.
The vehicle body member having such a closed sectional structure according to the present invention may include, for example, a structural member, as shown in FIG. 9, composed of a connecting member having a front roof 1c (consisting of a roof rail inner and a roof rail outer), a front side roof rail 2c (consisting of a front side outer panel and a side roof rail inner) and a front pillar 3d (consisting of a front side outer panel and a front pillar inner) connected to one another. The front side roof rail 2c is provided with a shut-off plate 4c in the interior thereof, the front pillar 3d is provided with a shut-off plate 5c in the interior thereof, and the front side roof rail 2c is provided with an injection port 6c. 
(Injection Process for Injecting Two-Pack Urethane Foam Composition)
The present inventors further have made extensive studies in order to solve the second problem referred to above and, as a result, have found that the two-pack urethane foam composition can be injected in a smooth fashion while achieving the desired purposes, by using as an injection apparatus a two-pack mix, high pressure foaming machine of a type mixing the two-pack urethane foam composition and jetting the composition under high pressure in a counter flow, and by setting a cream time to 3 seconds or less and a rise time to 10 to 120 seconds after the injection. In other words, the use of such an injection apparatus and the setting of the cream time and the rise time to such ranges can prevent the cured urethane foam from leaking outside from gaps and at the same time thoroughly avoid an occurrence of clogging during injection. The present invention, in a further aspect has been completed on the basis of this finding. It is to be noted herein that the term xe2x80x9ccream timexe2x80x9d referred to in this description is intended to mean a period of time from the start of the composition increasing its viscosity to the start time at which a gel strength can be recognized, and that the term xe2x80x9crise timexe2x80x9d referred to therein is intended to mean a period of time from the time of injection of the composition to the time of suspending the foaming.
More specifically, the present invention provides an injection process for injecting a two-pack urethane foam composition, in which, upon injecting the two-pack urethane foam composition in the closed sectional portion of the vehicle body member with a closed sectional structure, a cured urethane foam is produced therein by allowing the composition to foam and cure. The two-pack urethane foam composition is injected with the two-pack mix, high pressure foaming machine of a type mixing the composition and jetting it under high pressure under conditions where the cream time is set to as short as 5 minutes or shorter and the rise time is set to 10-120 seconds from the start of injection.
An injecting apparatus according to the present invention may comprise a manipulator movable to a desired position, a jet injector fixed to the manipulator, a supply device for supplying the foaming material to the injector, and a controller adapted to control the position of the manipulator so that the injector is aligned at the position in which the foaming material can be injected into the closed sectional structure of the vehicle body through an injection port of the same closed sectional structure thereof. The supply device can be controlled so that the foaming material can be injected and filled in the closed sectional structure thereof by only such an amount that is set so as to comply with the volume of the interior of the same sectional structure thereof. This construction of the injecting apparatus can inject and fill the foaming material into the closed sectional structure of each part of the vehicle body so as to adapt to a flow of a line on which a large number of vehicle bodies are conveyed in sequence. It is to be noted herein that the foaming material may include, for example, a two-pack urethane foam composition.
In accordance with the present invention, the injecting apparatus may be provided with a position detecting sensor for sensing an amount of deviation between the injector mounted on the manipulator and the injection port of the closed sectional structure of the vehicle body in such a manner that the amount of deviation is outputted from the position detecting sensor to the controller and the position of the manipulator is adjusted by the controller so that the amount of deviation becomes zero. Therefore, even if the vehicle body would deviate from the original position, the injecting nozzle can be aligned with each injection port of the closed sectional structure of the vehicle body in an accurate way.
Moreover, the present invention may further be provided with a monitor for monitoring the foamed and cured states of the foaming material in the interior of the closed sectional structure of the vehicle body, so that the monitor can single out a vehicle body with a non-filled portion where no foaming material is injected and filled in the closed sectional structure thereof, and determine and treat such a vehicle body as a defective product.
Furthermore, in accordance with the present invention, in cases where the monitor inspects the non-filled portion of the closed sectional structure of the vehicle body, where no foaming material is injected and filled therein, a reference image of the injection port can be corrected in accordance with the position of the non-filled portion in the interior of the closed sectional structure of the vehicle body, where no foaming material is injected and filled.
It is now to be noted herein that the two-pack urethane foam composition, as an object of the invention in aspects of a series of the invention, except for the two-pack urethane foam composition for urethane foam, that is, the injection method for injecting the two-pack urethane foam composition, the cured urethane foam-filled vehicle body member, the cured urethane foam-filling confirming method, the injection process for injecting the two-pack urethane foam composition, the injecting apparatus for injecting and filling in the closed sectional structure of the vehicle body, and the injecting method therefor, is not limited to a particular kind of the composition and may contain any optional composition that can be allowed to foam and cure at ambient temperature. Specifically, the two-pack urethane foam composition may include, for example, a two-pack composition consisting of the polyol compound as a major component, preferably, such as a polyether polyol obtainable by the addition reaction of the active hydrogen-containing compound, e.g., the poly-valent alcohol, bisphenols, amines, etc., with the alkylene oxide, preferably, such as the aromatic polyisocyanate, aliphatic or alicyclic polyisocyanate, aromatic aliphatic polyisocyanate, a modified product thereof, terminal NCO- containing urethane prepolymer obtainable by the reaction between the polyols and an excessive amount of such polyisocyanate compounds, etc. Further, for the two-pack urethane foam composition, the major component may be formulated with a foaming agent such as, for example, water, the chemical foaming agent of a thermally decomposable type (e.g., azodicarbodiamide, p,pxe2x80x2-oxy 15 bisbenzene sulfonyl hydrazide, etc.) or the inorganic foaming agent of a thermally decomposable type (e.g., sodium hydrogen carbonate, etc.) and, as needed, a reaction catalyst, foam stabilizer, coloring agent, plasticizer, filler, fire retardant, antioxidant, and so on. Particularly, it is preferred to formulate the two-pack urethane foam composition with such an additive so that the resulting cured material becomes hard. It is further to be noted that, for the invention relating to the injection process for injecting the two-pack urethane foam composition, it is preferred to adjust the two-pack urethane foam composition injected from the two-pack mix, high pressure foaming machine so as to set the cream time to 5 seconds or shorter and the rise time to 10-120 seconds.
Although the above aspects of the invention can achieve the corresponding effects as sought to be achieved by applying it singly, the combination of two or more of the above aspects of the invention as described above can achieve further favorable effects when taken in account from the viewpoint of the reinforcement of the rigidity of the closed sectional structure of the vehicle body and performance of soundproof properties.
For instance, when the invention relating to the two-pack urethane foam composition for urethane foam is combined with another of the aspects of the invention, the further effect of preventing the leakage of the injected two-pack urethane foam composition toward outside can be achieved, in addition to those effects as sought to be achieved by each of the above aspects. In particular, it can be noted herein that the present invention is designed so as to cause the two-pack urethane foam composition to fail to leak outside and expand from the closed sectional structure, so that the application of the aspect relating to the such two-pack urethane foam composition to each of the aspects relating to the injection method and the injection process for injecting the two-pack urethane foam composition can add the effects as sought to be achieved by each of the aspects for the injection method and process to the effects as achieved by the invention for the composition itself.
Moreover, upon reinforcing the closed sectional structure of the body of a vehicle such as an automobile, etc. by filling the cured urethane foam therein, the aspect relating to the two-pack urethane foam composition can be applied so as to confirm the injecting and filling of the cured urethane foam by the aspect relating to the cured urethane foam-filling confirming method by injecting the two-pack urethane foam composition in accordance with the aspect relating to the injection process for injecting the two-pack urethane foam composition while injecting and filling the composition in the interior of the closed sectional structure of the vehicle body automatically with the manipulator by using the aspect relating to the injecting apparatus for injecting and filling the urethane foam in the closed sectional structure. This configuration can inject and fill the closed sectional structure with an appropriate amount of the two-pack urethane foam composition without leaking the composition from the closed sectional structure, thereby reinforcing the closed sectional structure of the vehicle body and producing vehicles with their closed sectional structures reinforced therewith on a mass scale.
The features and effects to be achieved by the aspects of the invention as described above will become apparent to those skilled in the art in the course of the description which follows, with reference to the accompanying drawings and the appended claims.
Before turning to a detailed description of each embodiment of the aspects of the invention as described above, it is to be understood that each of the aspects is not limited to the application of a detailed disposition and construction of structuring elements as indicated in the accompanying drawings referred to in the following description. It is further to be understood that the aspects of the invention as described above can encompass other embodiments within the scope thereof and be performed and practiced by various processes and, in addition, that the terms and expressions as referred to herein are used singly for illustrative purposes and they should not be interpreted to limited meanings in any respect, unless otherwise stated herein and interpreted in that context.